1. Field of the Invention
The present invention relates to a single electron device fabricated from nanoparticle derivatives, and in particular to a single electron device fabricated from Au and fullerene nanoparticle derivatives.
2. Description of the Related Art
Single electron devices have the advantages of low power consumption and high packing density and thus have received much attention in various applications recently.
Referring to FIG. 1a, a schematic top view of the structure of a conventional single electron transistor is shown. In this FIG. 1a, ISO is an insulation structure; S and D are respectively a source electrode and a drain electrode, OX is a tunneling oxide layer; dot is a cluster of nanoparticles, which possesses a dot shape in three dimensional space and for which the lengths along the directions of x, y, and z axes in the coordinate system generally have to be less than 500 A (angstrom); and exe2x88x92 represents a moving electron. FIG. b shows the movement of an electron in the single electron transistor shown in FIG. 1a, wherein G is a gate electrode (not shown in FIG. 1a).
In the structure of the conventional single electron transistor (SET) mentioned above, the source electrode S, the nanoparticles, and the drain electrode D are isolated by the extremely thin tunneling oxide layer OX. Under a specific source-drain electrode bias, the electron from the source electrode can arrive at the nanoparticles first by passing through the tunneling oxide layer, and then arrive at the drain electrode by passing through the tunneling oxide layer, to facilitate the conductivity of the single electron transistor.
The operating temperature of SET depends on the geometrical size of the nanoparticles, that is, the smaller, the better, thus presenting a challenge to modern semiconductor manufacturing technology. Conventionally, the processes to fabricate SET are mostly related to e-beam lithography, and for resolution of limitations in space, the structural sizes constructed by the technology of e-beam lithography are still more than 10 nanometers. The methods of using nano-structured materials having critical sizes less than nanometers are presented to overcome the technical limitation mentioned above, however, it is difficult in practical applications to allow the nano-structured materials to contact electrodes, although the nano-structured materials can be prepared by synthesis technology. Therefore, the utilization of self-assembly nanometer building-blocks to fabricate nanodevices has become the most frequently investigated method, due to high feasibility.
Up to now, there have been many reports regarding the assemblies of two-dimensional arrays of quantum dots by lithography and epitaxy depositions. Alternatively, by way of the solution chemical process, a bridge can be formed by organic molecules such as alkyldithiols, surfactants, organic polymers, conjugated DNAs, or biomimic conjugated systems molecules to assist the regular assembly of metals, insulators, and semiconductor nanoparticles. Two- or three-dimensional nanoparticle arrays can be constructed through the formation of covalent bonds, hydrogen bonds, or van der Waals forces by the methods mentioned above. Therefore, the self-assembly process provides a feasible way to fabricate nanodevices.
Accordingly, the invention discloses single electron devices that can reduce thermal fluctuation of nanoparticle arrays due to fullerene derivatives presenting rigid carbon balls with good thermal stability, and moreover, Au and fullerene nanoparticle derivatives that overcome the size limitation of the semiconductor manufacturing skill to fabricate single electron devices with 15 nm spacing between two electrodes.
Accordingly, an object of the invention is to provide a single electron device fabricated from nanoparticle derivatives.
Another object of the invention is to provide a single electron device fabricated from Au and fullerene nanoparticle derivatives.
Still another object of the invention is to provide a nanoparticle derivative for use as a bridge linking to two electrodes.
A detailed description is given in the following embodiments with reference to the accompanying drawings.